CVE-2026-126134
Published Nov 10, 2026
Modified Nov 10, 2026
Description
Thunderbird allowed feed subscriptions to file: URLs that point to a network share. If a user was tricked into subscribing to such a URL, Thunderbird connected to the attacker's server when fetching the feed. Windows then sent the user's NTLM credentials to that server. This bug only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7.
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EPSS — Exploit Prediction
0.0020
Probability of exploitation
0.09%
Percentile rank
EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.
References
Frequently Asked Questions
What is CVE-2026-126134? +
Thunderbird allowed feed subscriptions to file: URLs that point to a network share. If a user was tricked into subscribing to such a URL, Thunderbird connected to the attacker's server when fetching the feed. Windows then sent the user's NTLM credentials to that server.
This bug only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7.
How do I check if I'm vulnerable to CVE-2026-126134? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.
